问题 解答题

在10件产品中,有3件一等品,4件二等品,3件三等品,从这10件产品中任取3件,求取出的3件产品中一等品件数X的分布列。

答案

解:由于从10件产品中任取3件的结果数为

从10件产品中任取3件其中恰有k件一等品的结果数为

那么从10件产品中任取3件,

其中恰有k件一等品的概率为P(X=k)=,k=0,1,2,3,

所以随机变量X的分布列是

阅读理解

阅读理解

     Thomas Wheeler, CEO (首席执行官) of a company, and his wife were driving along a highway

when he noticed that their car was low on gas. Wheeler got off at the next exit and soon found a rundown (破旧) gas station with just one gas pump. He asked the lone attendant (服务人员) to fill the tank and

check the oil, and then went for a little walk around the station to relax his legs.

     As he was returning to the car, he noticed that the attendant and his wife were talking excitedly. The

conversation stopped as he paid the attendant. But as he was getting back into the car, he saw the

attendant wave and hear him say, "It was great talking to you."

     As they drove out of the station, Wheeler asked his wife if she knew the man. She readily admitted

and she did. They had gone to high school together and had dated steadily for about a year.

     "Boy, were you lucky that I came along," bragged (自夸) Wheeler. "If you had married him, you'd be

the wife of a gas station attendant instead of the wife of a CEO."

     "My dear," replied his wife, "if I had married him, he'd be the CEO and you'd be the gas station

attendant."

1. How did the CEO feel when he saw his wife talking with the attendant?

A. strange and curious  

B. curious and angry  

C. happy and proud    

D. strange and proud

2. Which of the following statements is NOT right?

A. The attendant worked alone and couldn’t make much money.        

B. The wife stopped talking with the attendant as soon as her husband returned.

C. It seemed that the CEO and his wife had driven far before coming to the station.

D. The CEO's wife had once been the attendant's girlfriend for about a year.

3. The best title for the passage would be_____________.

A. Good marriage leads to a good life.  

B. A rich CEO and a poor attendant.

C. True love can last for a long time.  

D. Behind every great man is a great woman.

单项选择题